Most of the sphingolipidoses are known to affect the eye, leading usually to blindness. Although ultrastructural studies carried out with ocular tissues of patients indicate the deposition of residual bodies in lysosomes, systematic chemical and biochemical studies have not been performed. In the proposed study we will carry out an extensive chemical and biochemical analysis of the distribution of various sphingolipids in normal eye as well as experimental animals which are known to be genetic models for some of the sphingolipidoses. These studies will include isolation, characterization and quantitation of individual sphingolipid components. The natural substrates, purified from human tissues, after radioactive labeling, will be used for developing new assay systems for various sphingolipid hydrolases. The affinity chromatographic methods, developed in our laboratory, for the isolation of sphingolipid beta-galactosidases and beta-D-N-acetyl hexosaminidases in high yield and purity will be used to purify these enzymes from cornea, lens and retina. The structural, kinetic and immunological properties of these enzymes will be studied. These studies will be helpful in understanding the mechanism by which the disturbed sphingolipid metabolism leads to ocular pathogenesis. The proposed studies, besides explaining the genetic interrelationship between GM1 gangliosidosis and Krabbe's disease, will reveal the causes of differences in ultrastructural manifestations in the ocular tissues of the patients suffering from these diseases. The detection of cross-reacting material in various sphingolipidoses and possible development of radioimmunoassay using tears will be of great significance in detecting heterozygotes.